Security architecture in a multi-hop mesh network

1. Security architecture in a multi-hop mesh network Conference in France, 2006 2006. 9. 26. Presented by JooBeom Yun

2. Contents • Introduction • Problematic • State of the art and related works • Ad-hoc network security • Users’ access to wireless networks • Proposed security architecture • PANA framework • Technical description • Security analysis of the solution • Future works • Conclusions Security architecture in a multi-hop mesh network

3. Introduction • Multi-hop mesh network • Extension of a wireless mesh network by an ad hoc network • Authentication mechanism is essential • In wireless network and in an ad hoc network • The biggest problem • Authentication of the mobile node Security architecture in a multi-hop mesh network

4. Problematic • Multi-hop mesh network inherits from the security problems • Ad-hoc networks • Passive eavesdropping, message replaying, message distorsion, active impersonation • DoS • Mesh network (Fake APs) • Eavesdropping, tampering, DoS • Access control enforced by operators • Authentication, authorization • Protect data exchanges Security architecture in a multi-hop mesh network

5. State of the art and related works • Ad-hoc network security • Covers secure routing, key establishment, authentication, certification/revocation services • Secure routing • designed security protocols - ARAN[1], Ariadne[2], SAODV[3] • Certification and revocation services • Threshold cryptography[5,6], ID-based cryptography[7], both cryptography[8] • Users’ access to wireless networks • IEEE 802.1X standard • EAP(Extensible Authentication Protocol) messages between the user and the AP • PANA(Protocol for Carrying Authentication and Network Access) protocol • Medium independent solution • EAP messages to be carried over IP Security architecture in a multi-hop mesh network

6. Proposed security architecture • IEEE 802.1X • Mobiles may be authenticated by the mesh AR • Authentication is done at layer 2 (MAC address) • The mobile is assumed to be directly attached to the mesh routers • PANA • Authenticate using the IP protocol • EAP lower-layer • Any EAP method is suitable for authentication • PANA framework • Technical description • Security analysis of the solution Security architecture in a multi-hop mesh network

7. PANA framework • PANA Client (PaC) • Request authentication, provide the credentials • PANA Authentication Agent (PAA) • Interacts with the AS to determine the access control state and communicates EP • Enforcement Point (EP) • Controls access of a new node to the network • Authentication Server (AS) • Verify the credentials of a node requiring access to the network • Asked by the PAA Security architecture in a multi-hop mesh network

8. Technical description (1/3) Configuration (e.g. DHCPv4) PANA Discovery phase and begin of Authentication and authorization phase Authorization [IKE-PSK, PaC-DI, Session-id] PANA-Bind-Request / PANA-Bind-Answer IKE SA Security architecture in a multi-hop mesh network

9. Technical description (2/3) Encapsulation of EAP packets during PANA authentication Security architecture in a multi-hop mesh network

10. Technical description (3/3) • EAP-MD5 • Login/password • Known vulnerabilities (dictionary and brute-force attacks) • Does not support mutual authentication • EAP-TLS • Secure and robust against attacks • Mutual authentication • Protect network access by providing an IKE-PSK Security architecture in a multi-hop mesh network

11. PANA/EAP-TLS authentication procedure (1/2) PANA-Auth-Request (EAP-Request/Identity) ① ② PANA-Auth-Answer (EAP-Response/ Identity (MyID)) Access-Request (EAP-Response/ Identity (MyID)) ③ PANA-Auth-Request(EAP-Request/EAP-Type=EAP-TLS(TLS Start)) Access-Challenge(EAP-Request/EAP-Type=EAP-TLS(TLS Start)) ④ PANA-Auth-Answer(EAP-Response/EAP-Type=EAP-TLS(TLS Client-hello)) Access-Request(EAP-Response/EAP-Type=EAP-TLS(TLS Client-hello)) ⑤ PANA-Auth-Request(EAP-Request/EAP-Type=EAP-TLS(TLS Server_hello, TLS certificate, [TLS server_key_exchange,][TLS Certificate_request,] TLS server_hello_done)) Access-Challenge(EAP-Request/EAP-Type=EAP-TLS(TLS Server_hello, TLS certificate, [TLS server_key_exchange,][TLS Certificate_request,] TLS server_hello_done)) Security architecture in a multi-hop mesh network

12. PANA/EAP-TLS authentication procedure (2/2) ⑥ PANA-Auth-Answer (EAP-Response/ EAP-Type=EAP-TLS (TLS Certificate, TLS client_key_exchange, [TLS certificate_verify,] TLS Change_cipher_spec, TLS finished)) Access-Request (EAP-Response/ EAP-Type=EAP-TLS (TLS Certificate, TLS client_key_exchange, [TLS certificate_verify,] TLS Change_cipher_spec, TLS finished)) ⑦ PANA-Auth-Request(EAP-Request/EAP-Type=EAP-TLS(TLS Change_cipher_spec, TLS finished)) Access-Challenge(EAP-Request/EAP-Type=EAP-TLS(TLS Change_cipher_spec, TLS finished)) PANA-Auth-Answer (EAP-Response/ EAP-Type=EAP-TLS) EAP-Response/ EAP-Type=EAP-TLS PANA-Bind-Request (EAP-Success,Device-Id,[protection-Cap],MAC) Access-Accept(EAP-Success) PANA-Bind-Answer (Device-Id,[protection-Cap],MAC) Security architecture in a multi-hop mesh network

13. IPsec/IKE protection • Multi-hop environment • Access control need to operate at the network layer or upper layers • IPsec protocol suite • Support strong access control to authenticate packets’ origin • Provide data encryption (using ESP) • In order to setup an IPsec security • initiate IKE exchanges • authenticate to each other. Security architecture in a multi-hop mesh network

14. Security analysis of the solution (1/2) • Protection against replay attacks • Spoofing messages • Sequence numbers are randomly initialized at the beginning of the session • Protection against PaC DoS attacks • Spoofed message • MAC protection • Providing message integrity • Service theft attack • provides message integrity and protects the PaC’s identifier. • Spoofing PAA message • An attacker can spoof PAA messages • Less secure authentication method • negotiate parameters after the establishment of PANA security association Security architecture in a multi-hop mesh network

15. Security analysis of the solution (2/2) • PAA DoS attack • Overload the PAA with PANA-PAA-Discover messages • Add a cookie (Device ID) to the PANA-Start-Request message • DHCP DoS attack • DoS attacks are possible by depleting the IP address space • Other possible attacks • Ad-hoc and mesh networks • vulnerable to passive eavesdropping, message replaying, message distorsion, easy man-in-the-middle, active impersonation, DoS, IP spoofing • Cryptographic technics(IPsec) – prevent eavesdropping, message distorsion, active impersonation • Mesh networks • Worst DoS is not possible (using access control) • Access control, cryptographic technics Security architecture in a multi-hop mesh network

16. Future works • The proposed architecture • combines PANA with EAP-TLS in a multi-hop mesh network. • EAP-TLS • Mutual authentication and strong robustness against attacks • Heavy treatment (the use of asymmetric cryptography) • Need PKI • EAP-MD5 • Simpler • Vulnerable to eavesdropping attacks • Working • combine the simplicity of EAP-MD5 and the robustness of EAP-TLS • PANA exposes to IP address starvation in IPv4. • Adapting IEEE 802.1X to multi-hop mesh networks (new research direction) Security architecture in a multi-hop mesh network

17. Conclusions • Access network security in a multi-hop mesh network • access control • data protection • IEEE 802.1X standard • can be extended to support authentication in multi-hop mesh networks • It’s not easy (modify the standard) • A combination of EAP-TLS over PANA and IPsec has been proposed. • PANA is relying on the availability of IP addresses. • IPv6 • Temporary private addresses Security architecture in a multi-hop mesh network

18. Q & A Security architecture in a multi-hop mesh network